Since I upgraded to Jaguar, Print Center would always crash when I tried to set up a new printer. Solution: I deinstalled FaxSTF and since then Print Center works properly (the hint for the cause came from the console messages).
[Editor's note: I have no experience with FaxSTF, but thought this might help others who may be troubleshooting a crashing Print Center.]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20020913061936134